1. Field of the Invention
The invention relates to a respiratory mask device, more particularly, to a respiratory mask device having cantilever arms carrying head strap connectors.
2. Description of the Related Art
It is known to use respiratory masks, such as nasal masks, face masks, etc., for treatment of various respiratory conditions such as obstructive sleep apnea. When a respiratory mask is used, the respiratory mask is placed over the nose, or the nose and mouth of a patient and is held to the head of the patient using a head strap connected to the respiratory mask. When the head strap is tightened on the patent's head, the head strap pulls the respiratory mask to abut against the patient's face, thereby holding the respiratory mask in place. Generally, in order to stabilize the respiratory mask, pulling forces are applied to two points at left and right sides of the patient's nose, and to another two points substantially at left and right sides of the upper lip of the patient.
Referring to FIGS. 1 and 2, there is shown a respiratory mask device 1 disclosed in Taiwanese Patent Application No. 94111323, which is connected to a gas supply device 11. The respiratory mask device 1 includes a mask body 12 used to cover the nose and mouth of a patient, two upper connectors 13, two lower connectors 14, two upper head straps 15 connected respectively to the upper connectors 13, and two lower head straps 15 connected to the lower connectors 14. The mask body 12 can be held in place by fastening the upper and lower head straps 15 to the head of the patient. However, the following disadvantages are encountered by the respiratory mask device 1.
1. Because the upper connectors 13 are disposed at left and right sides of the patient's nose, when the upper head straps 15 are pulled rearward, the upper head straps 15 tend to cover parts of the patient's eyes, thereby causing discomfort to the patient.
2. Although the positions of the upper connectors 13 may be lowered slightly to change the position of the upper head straps 15 or to prevent the upper straps 15 from covering the patient's eyes, if the upper connectors 13 are lowered, they will become closer to the lower connectors 14, concentrating the points of application of pulling forces at the lower part of the mask body 12. As a result, the mask body 12 will become unbalanced and unstable, and the upper head straps 15 may exert uncomfortable pressure on part of the patient's ears.
Referring to FIG. 3, another respiratory mask device 2 in the prior art includes a mask body 21, two lower connectors 22 respectively connected to two lower head straps 24, and an extension strap 23 extending upwardly from the mask body 21 and having two upper connectors 232 which are connected respectively to two upper head straps 24. In this respiratory mask device, although the lower connectors 22 and the lower head straps 24 can balance the lower part of the mask body 21 and prevent the same from tilting leftward and rightward, because the upper connectors 232 are connected to the single extension strap 23, the upper part of the mask body 21 may tilt when subjected to an external force. In addition, because the extension strap 23 extends between the eyes of the patient, it May interfere with the patient's vision and cause inconveniences.